Dynamic control system for power sub-network

ABSTRACT

A dynamic power control system for controlling power utilization on a local level in a power sub-network of a power grid is presented. The power sub-network is configured with switchable power nodes, each having an associated priority level and each having a switch element that operates to switch coupling and uncoupling of first and second subsets of power lines in the sub-network. A sub-network controller monitors utility information that is associated with one of a plurality of system priority levels each of which is associated with one of a plurality of switch state configurations of the respective switch states of the switchable power nodes in the power sub-network, and effects the switch states of the switchable power nodes to comply with the switch state configuration associated with the received utility information.

BACKGROUND OF THE INVENTION

The present invention relates generally to power utilization and moreparticularly to a method and apparatus for controlling power utilizationin a power sub-network of a power grid based on external global powerparameters.

Large-scale electrical power distribution occurs over what is known inthe industry as a power grid. More particularly, a power grid is anexpansive network of high-voltage power transmission linesinterconnected at hundreds of power generating stations and distributionsubstations. The stations and substations are typically owned by variousutility companies, which manage distribution of power to various sectorsof the grid, including distribution of power to consumers overlower-voltage power lines that are stepped-down via transformers. Thesubstations essentially operate as power hubs, directing current frombranches with power surplus to branches needing additional power. Thepower substations thus operate to attempt to equalize distribution ofpower across the sectors of the grid and to allow the utilities to buyand sell electricity from each other. Substations may also transformsome of the power to a lower voltage level and direct it ontolower-voltage distribution lines that service local sectors. Endconsumers in the local sectors are fed through service lines that areconnected to the lower-voltage distribution lines.

Ohm's law is a basic law of the relationship between voltage,resistance, and current. The relationship can be expressed as I=V/R (orcurrent=voltage divided by resistance). This means that there is aninverse relationship between resistance and current, assuming thevoltage is held constant. In a discussion of how electricity isdelivered from the electrical power grid to the consumers of thatelectricity, it is a fair statement to say that it is the intent of theelectrical utility to provide a constant voltage for the electricalservice delivered to the consumers, and as much current as consumersdesire. It is also true that the consumers dictate the quantity ofcurrent being drawn at the intended voltage by varying the load(1/resistance) that the overall power grid experiences through theswitching on or off of electricity consuming devices such as lamps andmotors. As a result, in view of the fact that voltage is intended to befixed by the utilities and that consumers dictate the load based upontheir usage, that the current being drawn can be viewed as the dependentvariable in this relationship.

The electrical power grid is designed to be a balanced systemencompassing a number of power providers whose contributions vary asnecessary in order to meet the overall current requirements of theelectricity consumers. The grid or transmission infrastructure can beviewed, for the purposes of this patent, as a number of adjacenttransmissions lines linking the electricity producers and consumers, andover which the current is carried. For the purposes of this patent, thetransmission lines refer to all of the components that are not part ofthe electricity producer, not part of the electricity consumer, and thatare necessary for carrying current between the producers and consumers.

By design, these adjacent or effectively parallel transmission linesdivide and balance the carrying of the current necessary to satisfy theconsumers load, or demand, such that no individual transmission line isdamaged by attempted to carry an amount of current in excess of itscurrent carrying capacity.

There are typical two approaches taken by the utility service to reactto a situation where a transmission line is experiencing excessivecurrent. The first approach is to employ a current limiting device inseries with the system load. These devices typically react to increasesin heat from the overloading transmission line and become increasinglyresistive to current flow as the temperature of the transmission lineincreases. Use of devices like these limits the current being carriedover the transmission line, but results in either adjacent transmissionlines having to carry more current to meet effective demand, or in theconsumer experiencing decreased voltage at their location. Decreasedvoltage at the consumer's site is not acceptable since it can damagevoltage sensitive equipment that is expecting the voltage of theelectrical service to remain within reasonably tight acceptable limits.

The second option to react to excessive current on a transmission lineis to disconnect the transmission line that is overloading via the useof a manual or automated control device before damage to thetransmission line can occur. Unfortunately this approach has twonegative side effects. First, when one of the adjacent transmissionlines between the producers and the consumers of electrical current isdisconnected, whether intentionally or due to a fault, it places agreater current burden on the remaining adjacent transmissions lines.This additional current is know as a fault-current, and follows fromOhm's law which dictates that the full current required to satisfy thedemand still be delivered (assuming voltage is to be held constant), andis therefore divided over the remaining transmission lines as necessaryto achieve this. In this scenario, each of the adjacent transmissionlines will now be carrying an amount of current that is greater than thecurrent it carried prior to the fault having occurred—thus, theirproportion of the total current they carry increases.

As the adjacent lines near the point of overloading, automatedcontrollers disconnect them from the grid, increasing the number offault-current loads on other lines exponentially. If not controlledproperly, disconnecting transmission lines that are overloaded can thusresult in a cascading failure of the entire transmission system as thesame total current is attempted to be carried over a reduced number ofavailable transmission lines, possibly causing other transmission linesto become overloaded themselves and shutdown.

The objective to shutting down an overloaded transmission line istwo-fold. First, it is to protect the transmission line and itscomponents from damage resulting from the excessive current andresultant heat. The second reason is that often by shutting down atransmission line, the load will be disconnected from the electricalgrid, which will reduce the current required to satisfy the remainingload connected to the grid. This is a pruning of the power demand inorder to reduce the current to within levels that the transmission linescan support.

This approach to addressing the problem suffers from the fact that thegranularity at which the electrical grid can prune itself is extremelycoarse. Typically the granularity is at the neighborhood or regionalscale, but in the case of the blackouts of 2003, the scale of theblackouts became much greater.

There are two fundamental ways to address the issue of excessive currentthrough parts of the transmission system. The first is to increase thecurrent carrying capability of the transmission system. This approachfaces several challenges including resistance at the state and localregulatory levels, significant expense, and difficulty gaining right ofway for expansion of the transmission system.

The second approach is to reduce the electrical demand during times ofexcessive current draw. Reducing demand proportionally reduces thecurrent required, and reduces the risk of damage from excessive currenton the existing transmission system. These approaches are not mutuallyexclusive. Voluntary reductions in demand are attempted through the useof “realtime pricing” or “demand pricing”. With demand pricing, there isa financial disincentive to using power during high use periods. Clearlythis approach can, at best, only have a probabilistically positiveeffect on current draw, and at the present time could not be dependedupon as a means to control current draw during an unforeseen incidentsuch at the blackouts of 2003.

Accordingly, it would be desirable to have a technique for enabling thecontrol of electrical demand at a much finer granularity and in a muchmore selective way, than previously possible. As a result, during anelectrical disturbance, operators of the electrical grid would be ableto request the reduction of electrical load as necessary to reduce thecurrent on the transmission lines in an automated way with the resultbeing that load is reduced according to the electricity consumerspreferences for what is shutdown.

It would also be desirable to have a technique for allowing electricityconsumers to fully take advantage of the increasing trend in “realtimeelectricity pricing”, or “demand electricity pricing”. In realtime ordemand electricity pricing, the price for electrical power is adjustedmany times over the course of the day to better reflect the true cost ofelectricity production and transmission rather than being set lessfrequently based on averaging models. The advantage of this approachwould be that it allows consumers to adjust their consumption inresponse to changes in pricing. However, in order to take full advantageof this approach, the consumers need to be made aware of these pricechanges, and have a means for quickly adjusting their consumption inresponse to the changes in price. This invention allows consumers torespond in an automated fashion to rapid changes in the price ofelectricity. This ability provides potentially significant savings forconsumers, and can significantly reduce the peak electricity demand asseen by the electricity producing utilities. If peak electricity demandis reduced, then the current carrying capabilities of the electricitytransmission system are also reduced.

Separately, the utility companies, recognizing that there is a marketfor providing fast Internet services to households, are endeavoring toprovide Internet service using the power system wiring. To achieve this,several technologies have been invented, referred to as Broadband PowerLine (BPL) technologies, which use the existing Utility Service powerlines to provide a data communication channel that can be used toprovide Internet access to a customer. BPL technologies are primarilyintended to be inter-premises technologies. They are designed to provideInternet access to the home or business, in the same way that DSL andCable networking companies currently do.

Separately, intra-home networking is popular, but prior to theavailability of wireless networking, required wiring the premises fordata using one of several cable standards that are well known to someoneskilled in the art.

There are existing products available for utilizing the existingpremises electricity wiring for the purposes of home networking. Some ofthese products are based on the HomePlug standard. Products areavailable that allow one to bridge Ethernet communications into theHomePlug network which utilizes the electrical wires in the house. Thesebridges are plugged into a wall outlet, and provide a standard 10-Base-Tor 100-Base-T RJ-45 connector to connect the computer to. By utilizingtwo of these devices, the computers are networked, with thecommunications path taking advantage of the existing in-house, or“premises”, wiring. HomePlug enables the use of the premises electricalwiring to allow a communications network within the premises electricalnetwork.

SUMMARY OF THE INVENTION

As used herein, the term “utility” is meant to include all componentsnecessary to bring electricity to a consumer up to and including thepower meter where the electricity is measured at the consumer's site.The term “premises wiring”, as used herein, refers to all componentsnecessary to deliver the electricity from the electrical meter to theconsumer's electrical devices. Premises wiring would then include theservice coming into the site from the meter, the main electrical paneland any electrical sub-panels, and the site wiring, outlets, switches,and fuses, etc. The demarcation between the “utility” and “premises”wiring is presented herein for simplification of concept only and notlimitation, and is not necessary for the invention.

According to one aspect of the invention, a system is provide whichallows the electricity consumer to assign identification to eachelectrical outlet or circuit in the premises, and to develop a set ofrules to govern the turning on or turning off of each identified outletor circuit. The rules would include external information, some of itcoming from the utility company, during their evaluation. Examples ofinformation that might come from the utility company would include thecurrent cost of electricity, or whether a disturbance was occurring, andhow much the load needs to be reduced by to address the disturbance.Other information could be used as well. Information from other externalsources such as governmental agencies (e.g., the Office of HomelandSecurity), or from remote communication devices such as sensors, couldbe included in the information used when the rules are evaluated.

These rules are collectively referred to as a “policy”. The policy iscontinually or intermittently processed, and this processing results inthe appropriate outlets being turned on, or off, as specified by theevaluation of the policy.

In one embodiment, the invention includes a processing node at eachoutlet, with one of the processing nodes being responsible forprocessing the policy and communicating directives to the otherprocessing nodes. The node responsible for processing the policy and theexternal data may be called a master controller. In this approach,techniques for assuring the robustness of the master controller processor system would be employed such as fail over or leader election of themaster controller, or other techniques know to those skilled in the artof distributed computing, to ensure the robustness of the system.

In this embodiment, the invention implements or utilizes a communicationsystem between the external information sources such as the utilitycompany and the master controller in the premises sub-network that takesadvantage of the connectivity of the power lines in the power grid. Asan example, the emerging Broadband Power Line standard may be employedto allow communications between the utility company and the mastercontroller. Other communications mechanisms could be used as well, bututilization of the power lines coming to the consumer would be mostconvenient. This communications system would be used for eitherunidirectional or bi-directional communications between externalresources and the master controller. In the case of unidirectionalcommunications, the external resources would provide data or informationthat was evaluated in the processing of the policy. In bi-directionalcommunication, the master controller would be able to communicateinformation back to the external resources.

The invention would also implement a premises communications systembetween the master controller and the other processing nodes at theoutlets, or in the circuits. The premises communications system might bethe same, or different than, the utilities communications system used tocommunicate between the external entities and the master controller. Thepurpose of the premises communications system is for bi-directionalcommunications to allow the master controller to control the otherprocessing nodes, and for the other processing nodes to communicateinformation to the master controller. Ideally, the premisescommunications system would use the premises electrical wiring as thephysical layer of the communications system, and would be based onaccepted communications standards for use of the premises wiring, suchas the HomePlug standard.

According to another aspect of the invention, a system is provided thatwould allow refinement of the granularity with which a utility companyor other entity can control power usage in sub-networks of a power grid.Whereas, prior to the invention, utility companies only had the abilityto control power delivered to relatively large regions, or at bestindividual controllable power meters, the present invention provides theutility companies with the capability of controlling the consumer'spower demand with granularity down to specific outlets or circuits inpower sub-networks that implement the system of the invention.Additionally, because the control is dictated by a user specifiablepolicy, the users preferences are respected with regard to what outletsor circuits are disabled when necessary.

Clearly, it would also be beneficial to provide a mechanism for theexternal entities to force the turning off of outlets and circuits asnecessary. By communicating information such as the existence of a powerdisturbance that requires all non-essential power consumption bestopped, and assuming a policy that specifies rules that would cause thedisconnection of outlets identified as “non-essential”, and thus toremove their load from the cumulative electrical load, this systemallows the utility service to effect a significant reduction in theelectrical load in a very short time-frame through an automated meanswhile respecting the preferences of the electricity consumers.

Additionally, as electrical utilities are moving to demand pricing, thisinvention can be used to optimize the consumer's electricityconsumption. Assuming a demand pricing system where the current price ofelectricity is provided to the system implementing the invention, and apolicy that specifies the turning off of non-essential outlets aselectricity prices increase and the turning on of desirable outlets whenprices decrease, the invention provides a system that decreases theconsumption of electricity as the demand price increases, and visa-versain an optimal, automated process.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of this invention, and many of theattendant advantages thereof, will be readily apparent as the samebecomes better understood by reference to the following detaileddescription when considered in conjunction with the accompanyingdrawings in which like reference symbols indicate the same or similarcomponents, wherein:

FIG. 1 is a block diagram of a system that utilizes a dynamic powercontrol system in accordance with the invention;

FIG. 2 is a schematic block diagram of a switchable power node of theinvention;

FIG. 3 is a flowchart illustrating operation of the dynamic powercontrol system;

FIG. 4A is a packet format of a packet implementing a preferredembodiment of the content of utility information in accordance with theinvention;

FIG. 4B is a policy lookup table implementing a policy configurationformat;

FIG. 5 is a block diagram of a communication channel between a utilityinformation generator and a dynamic power control system using aBroadband Power Line protocol;

FIG. 6 is a block diagram of a communication channel between a utilityinformation generator and a dynamic power control system using a genericInternet protocol;

FIG. 7A is a block diagram illustrating a general communication channelbetween a master controller of a dynamic power control system of theinvention and a switchable power node;

FIG. 7B is a block diagram illustrating the communication channel ofFIG. 7A implemented using a power line physical transport protocol;

FIG. 7C is a block diagram illustrating the communication channel ofFIG. 7A implemented using a wireless transport protocol;

FIG. 7D is a block diagram illustrating the communication channel ofFIG. 7A implemented using a wired physical transport protocol;

FIG. 7E is a block diagram illustrating the communication channel ofFIG. 7A implemented using an analog radio-frequency physical transportprotocol;

FIG. 8 is a block diagram of a bi-directional communication channelbetween a master controller of a dynamic power control system of theinvention and switchable power nodes through intermediate nodes of thesystem;

FIG. 9 is a schematic block diagram of a priority level settingmechanism for a switchable power node;

FIG. 10 is a block diagram of a portion of a dynamic power controlsystem implementing an embodiment that allows discovery of switchablepower nodes in the system; and

FIG. 11 is a schematic block diagram of a preferred specific embodimentof a dynamic power control system that implements a registration andlookup service for routing messages between the master controller andswitchable power nodes.

DETAILED DESCRIPTION 1. General Embodiment

Turning now to the drawings, FIG. 1 is a block diagram of a system 1that utilizes a dynamic power control system 10 in accordance with theinvention. In this system 1, a power grid 2 is serviced by a utilitycompany 3. The utility company 3 provides electrical service 4 a–4 n toa plurality of entities (not shown) through an electrical service unit.More particularly, the utility company 3 supplies power 7 over regionaland local power lines 6 up to and including the electrical service units4 a–4 n (typically implemented by way of an electrical service meter 5).A power sub-network 10 distributes power beyond the electrical serviceunit over a sub-network of power lines 16 (e.g., premises wiring). Theuse of power within the power sub-network 16 can be dynamicallycontrolled using the dynamic power control system 10 of the invention.

Implementation of the dynamic power control system 10 of the inventionrequires utility information 8 generated by the utility company 3 orsome other external entity (e.g., a homeland security network site, notshown), one or more switchable power nodes 14 a–14 i to be monitored bythe system 1, a master controller 11 which receives the utilityinformation 8 and ultimately controls power delivery to devices servicedby the various switchable power nodes, and a power usage policy 12 whichdefines a set of power usage control rules that the master controller 11is to effect within the system 10 based on associated system conditions.

Although shown for convenience as a separate entity in FIG. 1, anyswitchable power node 14 a–14 i can itself act as the master controller11 as long as it can monitor the utility information 8, has access tothe policy 12, and can effect opening and closing of the switches ineach of the switchable power nodes 14 a–14 i being monitored by thesystem 10 via some sort of communication link 18 to the other switchablepower nodes 14 a–14 i. Furthermore, the master controller 11 need not befixed. For example, some protocols (e.g., Infiniband) allow anynetworked processing node to act as master through an arbitrationprotocol. A similar arbitration protocol could be used at theapplication layer of the invention to allow for failover and robustnessof the master controller. Alternatively it is also possible to developan embodiment where all switchable power nodes 14 a–14 i are considered“peers” (meaning there is not identified master controller), and eachswitchable power node 14 a–14 i is responsible for interpreting thepolicy and setting its own state appropriately. This approach wouldeliminate a single point of failure in the architecture. For simplicity,the illustrative preferred embodiment is described as having a single,fixed, master controller 11 and a plurality of switchable power nodes 14a–14 i.

A representative switchable power node 14 is shown in block diagram formin FIG. 2. A switchable power node 14, as defined herein, comprises (1)a switch element 17 that can electrically connect or disconnect one ormore power lines 16 input to the switch element 17 in-line with thesub-network wiring 16; (2) an electronic/electro-mechanical controlmechanism 18 that actuates the switch element 17; and (3) a switchcontrol interface 19 for activating the control mechanism 18 to actuatethe switch element 17 to connect or disconnect the power lines 16 inputto the switch element 17. A switchable power node 14 a–14 i can beimplemented anywhere along the sub-network power wiring, for example, atpower outlets, at junction boxes, at switches, at power breakers orfuses, or anywhere in-line with the sub-network wiring. If located at apower outlet, the switchable power node 14 may be implemented as a unitthat is plugged into one of the outlet sockets, or may be hardwiredin-line with the power lines going into the outlet box. Variousimplementations of the switchable power node 14 will be presentedhereinafter.

As previously described, the master controller 11 receives utilityinformation 8 generated by the utility company 3 or some other externalentity. Based on the utility information 8 received and the power usagepolicy 12, the master controller 11 controls power delivery to devicesserviced by the various switchable power nodes 14 a 14 i by effectingthe switch position (power connected or power disconnected) of thevarious switchable power nodes 14 a–4 i monitored by the dynamic powercontrol system 10.

a. Communication Between Utility Company/External Entity and MasterController

i. Content of Utility Information

Communication between master controller and electrical utility service(or other external service such as a homeland security service) isdictated by the service. The content of the utility information 8 mayinclude many types of information. In the illustrative embodiment, it iscontemplated that the utility information 8 will include at least one oftwo types of information: 1) status information (for example electricityrate information, which will change dynamically), and 2) controldirectives (for example, commands to turn off all switchable power nodesexcept nodes above a certain priority).

FIG. 3 is a flowchart illustrating operation 20 of the dynamic powercontrol system 10. As illustrated, utility information 8 is receivedfrom the utility company 3 (or other entity) (step 21). In the preferredembodiment, the utility information 8 may contain status information orcontrol directives. Accordingly, when utility information 8 received, adetermination is made (step 22) as to whether the utility information 8contains status information or a control directive. If the utilityinformation 8 contains status information, the policy 12 is consulted todetermine whether any action need be taken based on the received utilityinformation 8 (step 23). To this end, if the utility information 8affects any conditions on which the policy 12 requires that action betaken, the master controller 11 effects appropriate action (step 24),turning on or off the various monitored switchable power nodes 14 a–14 iaccording to the policy rules. If the utility information 8 isdetermined to contain a control directive (as determined in step 22),the system requires that action represented by the control directive betaken regardless of the policy 12. Accordingly, the master controller 11effects appropriate action (step 25), turning on or off the variousmonitored switchable power nodes 14 a–14 i according to the receivedcontrol directive.

Of course, the encoding and format of the utility information 8 dependsupon the physical transport of the information, discussed hereinafter.However, in general, the utility information 8 is recoverable from atransmission channel into a form shown in FIG. 4A. As shown therein, theutility information 8 comprises a type field 8 a and a payload field 8b. The content of the type field 8 a indicates whether the payload field8 b contains status, a control directive, or other content type (notdiscussed herein).

As just outlined, in the case that the type field 8 a of the utilityinformation 8 indicates that the payload 8 b contains statusinformation, the master controller 11 consults the policy 12 todetermine whether and how the status information should affect thesystem configuration (i.e., which switchable power nodes 14 a–14 ishould be connected to provide power and which should be disconnected toremove power from the devices it serves). In an illustrative embodiment,suppose the utility company 3 implements a dynamic utility rate that isbased on current electricity demand and that the utility information 8is status information containing realtime changes in electrically rateinformation so that the master controller 11 can implement rate-basedpolicy. Preferably, the policy 12 includes a set of rules allocating theswitchable power nodes 14 a–14 i being monitored by the system 10 tovarious rate categories. For example, a first subset of the switchablepower nodes 14 a–14 i in the power sub-network 10 may be assigned apriority level 1, a second subset of the switchable power nodes 14 a–14i in the power sub-network 10 may be assigned a priority level 2, athird subset of the switchable power nodes 14 a–14 i in the powersub-network 10 may be assigned a priority level 3, and so on in order ofimportance of the devices connected to the switchable power nodes 14a–14 i, where priority level 1 is the highest priority level, prioritylevel 2 is the second highest priority level, and so on. Accordingly,given the electrically rate information contained in the receivedutility information 8, the master controller 11 determines from thepolicy 12 that the rate falls within one of the priority levels. Themaster controller 11 then effects turning off all switchable power nodes14 a–14 i being monitored by the system 10 that have associated prioritylevels below the priority level associated with an electricity rangethat the current electricity rate falls within, and effects turning onall switchable power nodes 14 a–14 i having associated priority levelsin or above the priority level associated with the electricity rangethat the current electricity rate falls within. In other words, anelectricity rate change may trigger switchable power nodes 14 a–14 i tobe turned on or off by the dynamic power control system 10.

As an example, suppose that the utility information 8 is statusinformation containing rate information indicating that the rate is$0.0638/KW-hour. Suppose further that the policy 12 includes rulesallocating switchable power nodes to various rate categories,implemented as a simple lookup table 30 as illustrated in FIG. 4B. Inthis policy lookup table 30, each line represents a rate range and acorresponding priority level. Each line in the policy lookup table 30comprises three parameters delineated by a space. The first parameterindicates the lowest value in a given rate range, the second parameterindicates the highest value in the given rate range, and the thirdparameter indicates the lowest priority level that should be powered inthe sub-network (i.e., all switchable power nodes having a prioritylevel below that listed in the lookup table 30 for the current raterange should be switched to disconnect power through the switch). In theexample policy lookup table 30, a rate range between 0 and 0.0399 kWhcorresponds to a priority level of 8. Similarly, a rate range between 0and 0.0399 kWh corresponds to a priority level of 8; a rate rangebetween 0.0400 and 0.0499 kWh corresponds to a priority level of 7; arate range between 0.0500 and 0.0599 kWh corresponds to a priority levelof 6; a rate range between 0.0600 and 0.0699 kWh corresponds to apriority level of 5; a rate range between 0.0700 and 0.0999 kWhcorresponds to a priority level of 4; a rate range between 0.1000 and0.1999 kWh corresponds to a priority level of 3; and a rate rangebetween 0.2000 and 0.2500 kWh corresponds to a priority level of 2. Noline exists for a rate corresponding to a priority level of 1, becauseat least in this example policy, circuits on a priority level 1switchable power node are considered to be critical and should never beshut down.

Preferably, the various switchable power nodes 14 a–14 n in the system10 are assigned a priority level according to the level of importance ofthe devices connected down-line from a power node. (In this context, adevice that is “down-line” from a given switchable power node means thatpower flow can be cut off from the device by switching the switchablepower node to its isolated position and power can be restored to thedevice by switching the switchable power node to its connected position.

In the illustrative example, the current electricity rate is$0.0638/KW-hour. The current electricity rate falls within the raterange 0.0600 to 0.699, which corresponds to priority level 5.Accordingly, all switchable power nodes 14 a–14 n with a priority levelof 5 or greater are to be switched on (i.e., to provide an electricalconnection), and all switchable power nodes 14 a–14 n with a prioritylevel below 5 are to be switched off (i.e., to provide electricalisolation). In the given illustrative example, the master controller 11effects turning off all switchable power nodes assigned to priorities 3through 5, and turning on all switchable power nodes (if not already on)assigned to priorities 1 and 2.

in the case that the type field 8 a of the utility information 8indicates that the payload 8 b contains a control directive, the mastercontroller 11 effects the appropriate action defined by the controldirective. In the illustrative embodiment, the master controller 11 mustrespect these control directives regardless of whether they conflictwith the policy 12 because in the contemplated use, control directivesare only issued in emergency situations. (Of course, it will beappreciated that in alternative embodiments, control directives may beissued for other reasons or in non-emergency situations). For example,in the power blackouts of 2003, it was determined that the utilitycompanies had only a very small time window in which to significantlyreduce demand in the regions affected in order to prevent a problem. Byimplementing control directives that override the power sub-networkpolicy 12, a utility company 3 will be able to turn off switchable powernodes 14 a–14 i below a critical or important priority level in anautomated fashion in order to meet this stringent time limitation andavoid a power blackout.

As an illustrative embodiment, someone skilled in the art is capable ofbuilding a device which, as the temperature of the transmission lineincreases above a certain threshold temperature that indicates excessivecurrent on the transmission line, triggers the execution of a computerprogram running on a computer processor that generates and communicatesthe appropriate control directives that causes the invention to turn offan appropriate number of electrical devices and causes reduction inelectrical load sufficient to reduce the current on the transmissionline and avoid damage to the line.

ii. Physical Transport of Utility Information to Master Controller

Various methods exist to communicate utility information 8 to the mastercontroller 11 of a dynamic power control system 10.

In one preferred embodiment, the utility information 8 is presented onthe power grid power lines 6 coming into the power sub-network 10 at theelectrical service 4 a that pass through the meter 5. In this preferredembodiment, the utility information 8 is transmitted using a powercommunication protocol. In the preferred embodiment, the powercommunication protocol is the industry standard under development by theUnited States Federal Communications Commission (FCC) known as BroadbandPower Line (BPL), capable of delivering IP-based broadband services overthe electric power lines. In this embodiment, the system 10 requires aBPL modem designed to send and receive signals over electric power lines(much like cable and DSL modems send signals over cable and telephonelines). Access BPL carries broadband Internet traffic over mediumvoltage power lines (e.g., the power lines seen on top of utility polesthat carry several thousand volts). Electric utilities and their servicepartners can install BPL modems on the electric distribution network.Inductive couplers are used to connect BPL modems to the medium voltagepower lines. An inductive coupler transfers the communications signalonto the power line by wrapping around the line, without directlyconnecting to the line.

BPL Patents to Incorporate by Reference?

FIG. 5 illustrates an example BPL interface between a utility company 3and the master controller 11 of a dynamic power control system 10. Asillustrated, the utility company 3 transfers utility information 8communications signals onto the grid power lines 6 via a BPL modem 41 inseries with an inductive coupler 42. At the dynamic power control system10 where electrical service 4 a is provided to the local power lines 16,a BPL modem 43 is plugged into a socket up-line from the switchablepower nodes being monitored (for example, at the service meter 5). Anetwork cable or wireless connection 48 connects the BPL modem 43 to anetwork card 44 on either the master controller 11 or a network card 45on an independent computer 46 in communication with the mastercontroller 11 via communication link 47. The BPL modem 43 converts BPLsignals into a local network protocol understood by the mastercontroller 11.

In the embodiment of FIG. 5, the utility information 8 is transporteddirectly over the power lines 6, ensuring presentation of theavailability of the utility information 8 to all premises sub-networks.However, other methods for communicating utility information 8 to themaster controller 11 of a dynamic power control system 10 also exist.

In an alternative embodiment illustrated in FIG. 6, the mastercontroller 11 can use DSL, high-speed cable Internet, or other Internetservice to receive utility information 8 from the utility company 3. Theutility information 8 may pass directly from the utility company 3 tothe master controller 11 over a direct Internet connection 51, or passindirectly through one or more computers 50 via several differentInternet connections 52 and 53. Other implementations may be utilized aswell, for example, but not limited to cellular telephone technologies,wireless network technologies, etc., and other technologies that will bedeveloped over time. Of importance to any of these various technologies,as is well known by those skilled in the art, is the proper networkinterface layers that allow different computer systems to talk to oneanother via the network connection.

In summary, the utility company 3 (or another external entity) sendsutility information 8 to the master controller 11 of a dynamic powercontrol system 10. The system is implemented such that the utilityinformation 8 is passed to the master controller 11 in a formrecognizable by the master controller 11.

When using a TCPIP network protocol (over any of the physical transportlayers), the master controller 11 is identified by an IP addressassigned from the utility company (or other entity), similarly to howhigh-speed internet is provided currently through DSL or cable modemsusing one of the well-known protocols such as DHCP, static IP addresses,or PPPOE as appropriate.

Preferably, the master controller 11 can communicate with externalcomputers for logging purposes using well-known protocols such as UnixSyslog to create a time-series based log of events.

b. Communication Between Master Controller and Power Nodes

One of the critical functions of the master controller 11 is toimplement or execute the power usage policy 12, discussed hereinafter.To this end, based on a combination of the received utility information8 and the policy 12, the master controller 11 effects the policy 12, forexample by sending directives to the switchable power nodes 14 a–14 nthat are monitored by the system 10. Accordingly, the master controller11 must include a communications interface to communicate with theswitchable power nodes 14 a–14 n to actuate opening and closing of thepower node switches.

i. Physical Transport of Control Information from Master Controller toPower Nodes

The master controller 11 may communicate with the switchable power nodes14 a–14 n either directly or indirectly through one or more intermediatecontrol nodes.

FIGS. 7A–7E show various different embodiments for implementing theswitchable power nodes 14 a–14 n. FIG. 7A illustrates directcommunication between one embodiment of a master controller 11 a and aswitchable power node (SPN) 15 a. In this implementation, the mastercontroller 11 a must be configured with a switch control interface 60that generates a control signal 61 recognizable by the switch controlinterface 19 a of the switchable power node 15 a. The switch controlinterface 60 must therefore at least be able to transmit a controlsignal to the switch control interface 19 a of the switchable power node15 a in order to cause the switch control 18 a to actuate the switch 17a into either a connected position or a disconnected position. In someimplementations, the switchable power node 15 a may also include amemory 63 which stores a priority level associated with the switchablepower node 15 a or an electro-mechanical switch 64 whose state indicatesthe priority level of the switchable power node 15 a. In theseimplementations, it is often required that the switchable power node 15a also be able to return a signal 62 (for example, containing theswitchable power node's priority level) to the master controller or toan intermediate control node 99 b, as shown in FIG. 8. In this case, theswitch control interface 19 a of the switchable power node 15 apreferably also includes a transmitter for transmitting a signalrecognizable by the switch control interface 60 of the master controller11 a or switch control interface of an intermediate control node.Implementation of the prioritization levels of the switchable powernodes 14 a–14 n is discussed in more detail hereinafter.

FIG. 7B illustrates a more specific embodiment of direct communicationbetween one embodiment master controller 11 b and a switchable powernode 15 b. In this implementation, a master controller 11 b communicateswith a switchable power node 15 b over the sub-network power lines 16via a power line physical transport protocol 71 such as HomePlugPowerline developed by the HomePlug Powerline Alliance. In thisembodiment, both the master controller 11 b and switchable power node 15b are equipped with a power line physical transport protocol interface70 and 19 b, respectively, for example a Cogency HomePlug Powerline ASICwith an analog front end which makes the power line appear like anetwork connection by translating HomePlug Powerline signals into thelocal system interface format (MII, PCI, USB, 10Base-T, or others). Theswitch control circuitry 18 b translates the digital output of theHomePlug interface to an analog controller signal that actuates theswitchable power node switch 17 b.

FIG. 7C illustrates another embodiment of direct communication between amaster controller 11 c and a switchable power node 14 c. In thisimplementation, a master controller 11 c communicates with a switchablepower node 15 c over a wireless connection 81 via a wireless networkprotocol, for example using the IEEE 802.11 or 802.15 wireless networkprotocol. In this embodiment, both the master controller 11 c andswitchable power node 15 c are equipped with a wireless interface 80 and19 c, respectively. The switch control circuitry 18 c translates thedigital output of the wireless interface 19 c to an analog controlsignal that actuates the switchable power node switch 17 c.

FIG. 7D illustrates another embodiment of direct communication between amaster controller 11 d and a switchable power node 15 d. In thisimplementation, a master controller 11 d communicates with a switchablepower node 15 d over a wired connection 91, for example CAT5, co-axialcable, telephone lines, etc., using a wired network protocol such asEthernet, etc. In this embodiment, both the master controller 11 d andswitchable power node 15 d are equipped with a wired interface 80 and 19d, respectively. The switch control circuitry 18 d translates thedigital output of the wired interface 19 d to an analog control signalthat actuates the switchable power node switch 17 d.

In yet another embodiment, illustrated in FIG. 7E, a master controller11 e communicates with a switchable power node 15 e via radiocommunication 91. Master controller 11 e includes a radio transmitter90, and its corresponding switchable power node 15 e includes a radioreceiver 96 that is responsive to control signals 91 generated by theradio transmitter of its corresponding control node. The controlcircuitry that translates the received signal from the radio receiver 96into an actuating control signal for actuating the switch 17 e may beimplemented in analog 97 (for example, a notch filter tuned to aspecific actuating frequency) or digitally 98 (for example, using acombination of an analog-to-digital (A/D) converter, and a digitaldecoder/processor which converts the received analog signal to a digitalsignal that is decoded and turned into an actuating signal by aprocessor).

Other master-controller-to-power-node communication schemes may beimplemented. What is essential is that the master controller 11 is ableto open or close the switch 17 at each switchable power node 14 a–14 nvia a communication control signal. The communication control signal maybe any signal that the switch control node (or intermediate node) canrecognize and translate into a meaningful instruction for the switchablepower node (or pass on to one or more intermediate control nodes thatcan translate it into a meaningful instrument for the switchable powernode).

As briefly mentioned above, communication between the master controller11 and any of the switchable power nodes 14 a–14 n may occur throughintermediate communication with one or more intermediate control nodes.For example, FIG. 8 illustrates indirect communication between a mastercontroller 11 and a switchable power node 14 via one or moreintermediate control nodes 99 a, 99 b. Each intermediate control node 99a, 99 b in the master-controller-to-switchable-power-node communicationchain must be able to receive control information from either the mastercontroller 11 or a preceding intermediate control node 99 a, 99 b in themaster-controller-to-switchable-power-node communication chain and passon the control information to either the switchable power node 14 or asubsequent intermediate control node 99 a, 99 b in themaster-controller-to-switchable-power-node communication chain. Thecommunication links between the nodes 11, 99 a, 99 b, 14 in themaster-controller-to-switchable-power-node communication chain may eachuse the same or different communication protocols. Example embodimentsfor various communication protocols, for illustrative purposes only andnot by way of limitation, include TCP/IP or ATM as the network protocollayer over Homeplug, Ethernet, or Wireless 802.11 physical transportlayers, or radio communication, each described previously with respectto FIGS. 7B–7F.

Additionally, independent of the means by which the master controllercommunicates with a switchable power node, it is possible for theswitchable power node to make the communications available to either thedevice that is plugged into the switchable power node (in the case ofHomePlug style physical transport), or a device that is in receptionrange of the switchable power node (in the case of a wireless physicaltransport), or a device that can be connected to the switchable powernode (in the case of a wired connection). In this way, the switchablepower node can act as both a switchable power node and also anintermediate node in a chain that extends all the way to other devices.

ii. Relative Locations of Master Controller, Intermediate Nodes, andSwitchable Power Nodes

Each of the master controller and/or intermediate control nodes may beeither at or remote from a switchable power node.

c. Prioritization of Switchable Power Nodes

A priority level is assigned (either voluntarily or by default) to eachswitchable power node 14 a–14 i to be monitored.

Assigning a priority level to a switchable power node 14 a–14 i may beaccomplished according to one of several implementations. In oneembodiment shown in FIG. 9, the switchable power nodes 14 a–14 i areconfigured with a mechanical or electro-mechanical priority levelsetting mechanism 109 that allows a user to manually set the prioritylevel of the switchable power node at the switchable power node itself,utilizing an electro-mechanical switch 106 that may be manually switchedby the user at the switchable power node to set the priority level ofthe respective switchable power node between 1 and 8. Theelectro-mechanical switch 106 is connected to a set of eight fuses,transistors, resistors, or other switching elements 105. The set ofeight fuses, transistors, resistors, or other switching elements 105 areconnected on one end to the electro-mechanical switch 106 and on theother end to an 8:3 decoder 104 which translates the eight binaryswitches to a single hex value. The output of the 8:3 decoder 104containing the local priority level 107 is hardwired to store the localpriority level 107 in a memory location 103, which may be read by aprocessor 102 in the switch control interface 19 of the switchable powernode 14.

In one embodiment, the local priority level 107 is transmitted by theswitch control interface communication interface 101 to the mastercontroller 11 via the master controller-to-switchable power nodecommunication chain described above with respect to FIGS. 7A–7F or 8. Inthis implementation, the master controller 11 knows the local prioritylevel 107 of each switchable power node 14 a–14 i and can activelyeffect control of the switches in each of the switchable power nodes 14a–14 i.

In an alternative embodiment, the switch control interface 19 isconfigured to be more intelligent. In this alternative embodiment, themaster controller 11 broadcasts commands to all the switchable powernodes 14 a–14 i, preferably simultaneously, indicating, for example, aminimum priority level at which power should be connected. In thisembodiment, a processor 102 is implemented in each of the switch controlinterfaces 19 which respectively process the broadcast command, comparesthe local priority level 107 associated with the respective switchablepower node 14 a–14 i to the minimum priority level, and actuates itsrespective switch 17 to the power connected position if its localpriority level 107 is at or above the minimum priority level (if notalready in the power connected position), and actuates the switch 17 tothe power disconnected position if its local priority level 107 is belowthe minimum priority level (if the switch 17 is not already in the powerdisconnected position).

FIG. 10 illustrates a portion of the system, including an embodiment 110of a master controller 11 and an embodiment 120 of a switchable powernode 14 which implements proactive switchable power nodes. In thisembodiment, the master controller 110 (or other computer incommunication with the master controller 110) includes a switchablepower node discovery function 117 which actively seeks out availableswitchable power nodes 14 a–14 i in the system 10 and builds aswitchable power node list 118 that includes all switchable power nodes14 a–14 i in the system that are available to be monitored. Thediscovery function 117 may be implemented in one of several ways.

In one embodiment, if each switchable power node 14 a–14 i isimplemented as SPN 120 with a switchable power node identifier (SPN ID)134 (such as a Media Access Control (MAC) number or address) and apriority level setting mechanism 136 (such as 100 illustrated in FIG.9), the discovery function 117 can visit each possible address ofswitchable power nodes 14 a–14 i (for example a range of switchablepower node identifiers, where each switchable power node 14 a–14 i ishardwired or manually set to a different switchable power nodeidentifier 14 a–14 i ). For each possible identifier (e.g., MAC address)of switchable power nodes 14 a–14 i , the discovery function 117 canattempt to establish a communication connection with a switchable powernode 100 that has a switchable power node identifier 134 matching thatof the current possible identifier of switchable power nodes. Ifcommunication is established with a switchable power node having anidentifier that matches the identifier being tested, the discoveryfunction 117 issues a read request of the local priority level 135 ofthat switchable power node 14 a–14 i . The switchable power nodeidentifier 134 and its corresponding local priority level 135 are addedto the switchable power node list 118.

In an alternative embodiment, the switchable power nodes 14 a–14 i maybe configured to actively register with the master controller 11 uponpower up or installation in the system 10. A system implementing thisembodiment is discussed in detail hereinafter with respect to FIG. 11.

Referring back to FIG. 10, once a switchable power node list 118 hasbeen built, the master controller 110 has the information it needs(i.e., the power node address) for communicating with each of the activeswitchable power nodes 14 a–14 i . In the above described embodiments,after the discovery process, the master controller 110 also has thelocal priority levels 135 of each of the active switchable power nodes14 a–14 i.

In yet another embodiment, the master controller 11 may be configured toset the local priority levels of the switchable power nodes 14 a–14 i inthe system 10, for example if the switchable power nodes 14 a–14 i arenot configured with a priority level setting mechanism 109 or if it isdesired to allow the master controller 11 to be able to override themanual settings of the priority level setting mechanisms 109 at thoseswitchable power nodes 14 a–14 i . In this embodiment, using theswitchable power node list 118, the master controller 110 can visit eachactive switchable power node 14 a–14 i , and actively set its localpriority level 135, and/or simply set the local priority levelinformation associated with each switchable power node 14 a–14 i in theswitchable power node list 118.

In yet another embodiment, the local priority levels 135 of each of theswitchable power nodes 14 a–14 i may be set by a system administratorthrough a graphical user interface 115 (implemented either on the mastercontroller 110 or on another computer that communicates with the mastercontroller 110). The graphical user interface (GUI) 115 can be verysimple, allowing the system administrator to enter the switchable powernode identifier 134 and an associated local priority level 135 for eachswitchable power node 14 a–14 i in the system, or it can be morecomplex, integrating the discovery function 117 and switchable powernode list 118 to have the system find all available switchable powernodes 14 a–14 i and their identifiers in the system, present them to theadministrator, and allow the administrator to set or change the currentlocal priority levels 135 of the various switchable power nodes 14 a–14i in the system 10. To assist with identification of the switchablepower nodes 14 a–14 i , the GUI 115 may allow the system administratorto enter identifying information such as meaningful text that identifiesthe physical location of the node in the sub-network or devices servicedby the node in the sub-network.

d. Policy Configuration

The policy 12 includes a set of rules or other meaningful data thatallows the master controller 11 to dynamically effect systemconfiguration (i.e., controlling the switchable power nodes 14 a–14 i )in the system 10 in response to realtime utility information 8. Thepolicy 12 will typically be in the form of a data file in memory thatthe master controller processor reads; however, it may also beimplemented as an Application Specific Integrated Circuit (ASIC) orother hardware circuit. An example embodiment of a power usage policyfile 30 implementing the policy 12 was described previously with respectto FIG. 4B.

If the policy 12 is implemented as a data file, the data file may befixed by some entity such as the utility company 3, a homeland securityagency (not shown), or a commercial entity. If the data file is fixed,it is not configurable by individual system users, and may simply beloaded into a computer memory accessible by the master controller 11 orother computer node in communication with the master controller 11.

However, it may be advantageous to allow individual systemadministrators to configure the policy 12 specific to their own system10. In this case, the system administrator may be required to manually(i.e., via a computer text editor) generate the data file implementingthe policy 12 according to a specific format. Preferably, however, thesystem 10 includes a configuration policy function 114 integrated with agraphical user interface 115 that allows the system administrator toconfigure the policy 12 automatically through a user-friendly interface.

e. Specific Embodiment

FIG. 11 is a schematic block diagram of a preferred specific embodimentof a dynamic power control system 200 implemented according to theprinciples of the invention.

In the preferred embodiment 200, each of the switchable power nodes 14a–14 i preferably includes a priority level setting mechanism 109, suchas that described with respect to FIG. 9, to allow manual local prioritylevel setting at each node. In addition, each switchable power node 14a–14 i includes a local switchable power node identifier 108 whichuniquely identifies its respective switchable power node 14 a–14 iwithin the system 200.

The master controller 11 and switchable power nodes 14 a–14 i includesoftware that implements a lookup service 206 (for example, a Jini™lookup service using the Psynaptic™ JMatos™ lookup service such as thatdescribed in Smith, L., Roe C., and Knudsen K., “A Jini™ Lookup Servicefor Resource-constrained Devices”, presented at the 4^(th) IEEEInternational Workshop on Networked Appliances, Jan. 15–16, 2002,incorporated by reference for all that it teaches) to allow dynamicdiscovery and registration as switchable power nodes 14 a–14 i are addedor removed from the system. To this end, each control node (mastercontroller 11 and switchable power nodes 14 a–14 i ) discovers andregisters with the lookup service 206 (e.g., discovers and registerswith the master controller's JINI® lookup service using the JINIprotocols). The control nodes 11 and 14 a–14 i provide objects to thelookup service 206 that behave as remote proxies to the respectivenodes, providing the ability for the master controller 11 to access theobjects on the switchable power nodes 14 a–14 i and vice versa. Thus,when methods or functions are called on a remote proxy, the effects ofthose methods or functions are executed on the node providing theservice.

When the master controller 11 is initialized, it registers with thelookup service (LUS) 206 (e.g., implemented, for example, using aUnicast Request/Response to/from a Jini™ LUS, described in The Jini™Technology Core Platform Specification, The Jini™ ArchitectureSpecification and related documentation, all developed, published, andmade available by Sun Microsystems, Inc. of Santa Clara, Calif., andwhich is incorporated by reference for all that it teaches). Onceregistered, the master controller creates a service registrar 208 on themaster controller 11 through which all subsequent messages from themaster controller 11 are broadcast to the various switchable power nodes14 a–14 i through the LUS 206. When a switchable power node 14 a–14 i isadded to the system (either at power up or reset of the switchable powernode), it registers with the lookup service 206 (for example, using aUnicast Request/Response to/from the Jini™ LUS 206). Once registered, aswitchable power node 14 a–14 i creates a local service registrar 223 inits local memory 221. All messages received from the master controller11 and sent to the master controller 11 are then handled by LUS 206.Accordingly, in this embodiment, the LUS 206 is used to allow dynamicaddition and removal of switchable power nodes 14 a–14 i in the dynamicpower control system 200 monitoring a power sub-network of a power grid.The master controller 11 may register for event notification (forexample, the addition/removal of an switchable power node 14 a–14 i ) toallow it to update the switchable power node list 207 of activeswitchable power nodes 14 a–14 i and their associated local prioritylevels 207.

In the preferred embodiment, the communication link 215 between themaster controller 11 and switchable power nodes 14 a–14 i is preferablya TCPIP network protocol layered over either a wireless (e.g., Bluetooth802.11 standard) or a wired (e.g., Ethernet standard) physical transportlayer. Accordingly, each of the master controller 11 and switchablepower nodes 14 a–14 i includes a local control network API 203 and 225,respectively, that allows sending and receiving of information over thecommunication link 215.

The system 200 also includes a remote computer 210 that communicateswith the master controller 11 via a communication link 209 implemented,for example, using an HTML protocol layered over a TCPIP networkprotocol layered over either a wireless (e.g., Bluetooth 802.11standard) or a wired (e.g., Ethernet standard) physical transport layer.Accordingly, each of the remote computer 210 and master controller 11includes a remote computer network API 211 and 205, respectively, thatallows exchange of information over the communication link 209.

The master controller 11 includes a web server 204 for configuring thepolicy 12 and displaying/setting local priority levels 207 of theswitchable power nodes 14 a–14 i monitored by the system 200. The webserver 204 serves up web pages to a graphical user interface 212implemented on the remote computer 210.

The web server 204 may include a configure policy interface that allowsa system administrator to customize the policy 12 to the specificconfiguration of the switchable power nodes 14 a–14 i of the sub-networkbeing monitored. Customized policy configuration values may be writtento a data file implementing the policy 12. For example, given theexample policy data file 30 of FIG. 4B, the web server 204 may serve upweb pages to the graphical user interface 212 that allows the systemadministrator to change the electricity rate ranges and/or prioritiesassociated with those ranges.

The web server 204 may also include a configure local priority levelinterface that allows the system administrator to display and edit thelocal priority levels of the various monitored switchable power nodes 14a–14 i .

The web server 204 may also include a configure switchable power nodeinterface that allows the system administrator to add and removeswitchable power nodes 14 a–14 i from the system.

It will of course be appreciated by those skilled in the art that theweb server 204 may be implemented at the master controller 11 or on aremote computer that can transmit the policy 12 or policy changes to themaster controller 11. In addition, it will be appreciated by thoseskilled in the art that the web server functionality may bealternatively implemented, for example, using well-known client-servermethodologies such as socket connections and SNMP.

To receive utility information 8 from either a utility company 3 oranother entity 230, the master controller 11 includes a utility networkapplication program interface (API) 201. In the preferred embodiment,the utility information 8 is converted from a local format at theutility company 3 or other entity 230 to a network protocol. In oneillustrative embodiment, for example, the utility information 8 is sentvia network protocol using a network transport layer such as TCPIP,Novell IPX or SPX, ATM, etc. over a BPL physical transport layer via autility network API 231 and a BPL modem 41. The signal is then coupledonto the power lines of the power grid serviced by the utility company 3by way of an inductive coupler 42. At the power sub-network in which thedynamic power control system of the invention is implemented, a BPLmodem 43 converts the BPL signals present on the power lines of the gridto a local format by way of a utility network API 201, and the utilityinformation 8 is extracted.

In an alternative illustrative embodiment, the utility information 8 issent via a network protocol using a network transport layer such asTCPIP, Novell IPX or SPX, ATM, etc. over a wireless physical transportlayer such as Bluetooth 802.11 or wired physical transport layer such asDSL or High-Speed Cable Internet. The signal is then converted to alocal format by the utility network API 201 and the utility information8 extracted.

In operation, the local priority levels of the switchable power nodes 14a–14 i in the system are added to the sub-network system and configuredeither actively via the configure local priority level interface andconfigure switchable power node interface described above, orautomatically via the dynamic registration and lookup service describedabove. The policy 12 is either fixed and loaded into accessible memory,or loaded and configured via the configure policy interface describedabove.

After system configuration, utility information 8 is received by themaster controller 11. The processor 202 executes control software 250that processes incoming utility information 8. In the preferredembodiment, if the utility information contains status information(e.g., electricity rate information), the control software 250 accessesthe policy 12 and acts according to rules defined within the policy 12.If the policy dictates a change in the current configuration of theswitchable power nodes 14 a–14 i in the system 200 based on the statusinformation contained in the utility information 8, the control software250 generates an appropriate configuration change event message to bebroadcast by the lookup service 206. The service registrars of each ofthe switchable power nodes 14 a–14 i registered with the lookup service206 then receive notification of the configuration change. For example,the configuration change event message may contain merely the minimumpriority level that any given switchable power node should provide powerto their serviced devices. Thus, if the minimum priority level announcedin the configuration change event is for example, “4”, then allswitchable power nodes 14 a–14 i receive notification of the minimumpriority level, and their local control software 222 effects actuationof the respective switch 17 of the respective switchable power node 14a–14 i to ensure that if the local priority level 107 is at or above theminimum priority level, the switch is in the “connected” position, andif the local priority level 107 is below the minimum priority level, thesoftware is in the “disconnected” position.

If the utility information 8 contains a control directive (e.g.,emergency shut-off/turn-back-on information), the control software 250overrides the policy 12 and acts according to rules defined by emergencyor utility standards requirements. If the control directive dictates achange in the current configuration of the switchable power nodes 14a–14 i in the system 200, the control software 250 generates anappropriate configuration change event message to be broadcast by thelookup service 206, and the change is effected in the same way it iseffected for configuration changes based on mere status changeinformation, as described above.

F. Summary

The dynamic power control system for power grid sub-networks describedin detail above affords several advantages over the prior art. First,the system allows dynamic power usage in a given sub-network based onrealtime changes in electricity rate information. This allows asub-network to take advantage of changes in electricity rates to powercertain devices in times of low electricity demand (and hence, typicallylower rates) but disallow use of the devices during periods of highdemand (and hence, typically higher rates). It also naturally activelyforces reduction in demand for electricity as the natural demand forelectricity increases, helping to prevent power blackout situations.Finally, certain configurations of the system allow absolute commanddirectives from the utility companies or other entities (such asHomeland Security Agencies) to force immediate reduction in power usagethroughout the system for use in emergencies to avoid blackoutsituations.

The invention is extremely versatile in that it may be implementedaccording to any number of different ways. In summary, what is requiredis a number of switchable power nodes that service devices of varyingpower priority levels, a master controller that can effect turning on oroff of power supplied to devices serviced by the various switchablepower nodes, a communication link between the utility company or otherentity and a master controller of a local sub-network, a rule-basedpolicy describing switchable power node configuration requirements basedon possible incoming utility information, and a communications linkbetween the master controller and each of the switchable power nodes toallow the master controller to control turning on or off power to thedevices serviced by their respective switchable power nodes.

Although this preferred embodiment of the present invention has beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims. It is also possible that otherbenefits or uses of the currently disclosed invention will becomeapparent over time.

1. A dynamic power control system for a power network, comprising: oneor more switchable power nodes, each having an associated priority leveland each comprising a switch element that operates in a first state toelectrically couple a first subset of a plurality of power lines and asecond subset of said plurality of power lines and that operates in asecond state to electrically isolate said first subset of said pluralityof power lines from said second subset of said plurality of power lines,and a switch actuator that actuates said switch element to a switchstate, said switch state comprising one of said first state, said secondstate, and zero or more additional states; a control function whichreceives utility information that is associated with one of a pluralityof system priority levels each of which is associated with one of aplurality of switch state configurations of said respective switchstates of said one or more switchable power nodes in said power network,and effects actuation of said respective switch actuators ofcorresponding one or more of said one or more switchable power nodesthat require actuation to comply with said respective switch stateconfiguration associated with said received utility information; and aswitchable power node configuration setting function for setting saidrespective priority levels respectively associated with said respectiveone or more switchable flower nodes.
 2. The dynamic power control systemof claim 1, wherein: said utility information comprises electricity rateinformation.
 3. The dynamic power control system of claim 1, wherein:said utility information indicates a present level of available power tosaid system.
 4. The dynamic power control system of claim 1, wherein:said control function receives a command to effect compliance with oneof said plurality of switch state configurations; and said controlfunction effects actuation of said respective switch actuators ofcorresponding respective one or more switchable power nodes, if any,that require a respective change in said respective switch state tocomply with said one of said plurality of switch state configurationswithout regard to said respective associated priority levels of said oneor more switchable power nodes.
 5. The dynamic power control system ofclaim 1, wherein: said control function actively determines which, ifany, of said respective one or more switchable power nodes requires arespective change in its respective switch state in order to comply withsaid respective switch state configuration associated with said receivedutility information, and effects actuation of said respective switchactuators, if any, of said respective one or more switchable power nodesthat require said respective change in its respective switch state tocomply with said respective switch state configuration associated withsaid received utility information.
 6. The dynamic power control systemof claim 1, wherein: each of said one or more switchable power nodescomprises a respective local control function which determines whether arespective change in said respective switch state of said respectiveswitch element is required based on said respective switch stateconfiguration associated with said received utility information and saidrespective priority level associated with said respective switchablepower node, and which effects actuation of said respective actuator ofsaid respective switch element to change said respective switch state ofsaid respective switch element if said respective change in saidrespective switch state is determined to be necessary.
 7. The dynamicpower control system of claim 1, wherein: the plurality of systempriority levels comprises at least three system priority levels each ofwhich is associated with different ones of the plurality of switch stateconfigurations.
 8. The dynamic power control system of claim 1, wherein:said switchable power node configuration sailing function comprises arespective local priority level setting function at each of saidswitchable power nodes for setting said respective priority levelsrespectively associated with said respective one or more switchablepower nodes.
 9. The dynamic power control system of claim 8, wherein:said respective local configuration setting function comprises amechanical switch element that allows selling of said respectivepriority level associated with said respective switchable power node.10. The dynamic power control system of claim 1, wherein: saidswitchable power node configuration setting function comprises a webserver that obtains priority level information from a user andcommunicates with said one or more switchable power nodes to set saidrespective priority levels associated with said respective one or moreswitchable power nodes based on said obtained priority levelinformation.
 11. The dynamic power control system of claim 1, wherein:said switchable power node configuration selling function is remote fromsaid respective one or more switchable power nodes.
 12. The dynamicpower control system of claim 11, wherein: said switchable power nodeconfiguration setting function comprises a web server that Obtainspriority level information from a user and uses said obtained prioritylevel information to configure said respective priority levelsassociated with said respective one or more switchable power nodes. 13.The dynamic power control system of claim 1, further comprising: apolicy configuration function for configuring associations between aplurality of possible utility information for receipt by said controlfunction and said plurality of system priority levels, and/orconfiguring associations between said plurality of system prioritylevels and said respective one or more switch state configurations ofsaid respective switch states of said switchable power nodes in saidpower network, and/or configuring said respective one or more switchstate configurations of said respective switch states of said switchablepower nodes in said power network; and wherein said control functionassociates said received utility information with an associated systempriority level and associates said associated system priority level withan associated switch state configuration in accordance with saidconfigured associations between said plurality of possible utilityinformation and said plurality of system priority levels, and/or saidconfigured associations between said plurality of system priority levelsand said respective one or more switch state configurations, and/or saidconfigured respective one or more switch state configurations of saidrespective switch states of said switchable power nodes in said powernetwork.
 14. The dynamic power control system of claim 13, wherein: saidpolicy configuration function comprises a web server that obtainsconfiguration information from a user and uses said obtainedconfiguration information to configure said system.
 15. The dynamicpower control system of claim 1, further comprising: a utilityinformation communication interface comprising a data communicationchannel implemented over an active power line coupled to said dynamicpower control system which receives said utility information over saidcommunication channel.
 16. The dynamic power control system of claim 1,further comprising: a utility information communication interfacecomprising a data communication channel over which said utilityinformation is transmitted from a utility information generator.
 17. Amethod for dynamically controlling power usage in a power network, saidmethod comprising the steps of: receiving utility information;associating said utility information with one of a plurality of systempriority levels; associating said one of said plurality of systempriority levels with one of a plurality of switch state configurationseach representing a particular configuration representing respectiveswitch states of one or more switchable power nodes in said powernetwork, each said one or more switchable power nodes having anassociated priority level and comprising a switch element that operatesin a first state to electrically couple a first subset of a plurality ofpower lines and a second subset of said plurality of power lines andthat operates in a second state to electrically isolate said firstsubset of said plurality of power lines from said second subset of saidplurality of power lines, and a switch actuator that actuates saidswitch element to a switch state, said switch state comprising one ofsaid first state, said second state, and zero or more additional states;and effecting actuation of said respective switch actuators ofcorresponding one or more of said one or more switchable power nodesthat require actuation to comply with said respective switch stateconfiguration associated with said one of said priority levels that isassociated with said received utility information.
 18. The method ofclaim 17, wherein: said utility information comprises electricity rateinformation.
 19. The method of claim 17, wherein: said utilityinformation indicates a present level of available power to said system.20. The method of claim 17, wherein: said utility information comprisesa command to effect compliance with one of said plurality of switchstate configurations; and said step of effecting actuation compriseseffecting actuation of said respective switch actuators of correspondingrespective one or more switchable power nodes, if any, that require arespective change in said respective switch state to comply with saidone of said at least three switch state configurations without regard tosaid respective associated priority levels of said one or moreswitchable power nodes.
 21. The method of claim 17, wherein said stepfor effecting actuation further comprises: actively determining which,if any, of said respective one or more switchable power nodes requires arespective change in its respective switch state in order to comply withsaid respective switch state configuration associated with said receivedutility information; and effects actuation of said respective switchactuators, if any, of said respective one or more switchable power nodesthat require said respective change in its respective switch state tocomply with said respective switch state configuration associated withsaid received utility information.
 22. The method of claim 17, whereinsaid step for effecting actuation further comprises: informing said oneor more switchable power nodes of said respective switch stateconfiguration associated with said received utility information; whereineach of said one or more switchable power nodes respectively comprises arespective local control function which determines whether a respectivechange in said respective switch state of said respective switch elementis required based on said respective switch state configurationassociated with said received utility information and said respectivepriority level associated with said respective switchable power node,and which effects actuation of said respective actuator of saidrespective switch element to change said respective switch state of saidrespective switch element if said change in said respective switch stateis determined to be necessary.
 23. The method of claim 17, furthercomprising: configuring at least one of a plurality of configurationparameters, said plurality of configuration parameters including one ormore of; (a) associations between a plurality of possible utilityinformation for receipt by said control function and said plurality ofsystem priority levels, (b) associations between said plurality ofsystem priority levels and said respective one or more switch stateconfigurations of said respective switch states of said switchable powernodes in said power network, (c) said respective one or more switchstate configurations of said respective switch states of said switchablepower nodes in said power network, and (d) said respective prioritylevels respectively associated with said respective one or moreswitchable power nodes.
 24. The method of claim 17, wherein: theplurality of system priority levels comprises at least three systempriority levels each of which is associated with different ones of theplurality of switch state configurations.
 25. A computer readablestorage medium tangibly embodying program instructions which, whenexecuted by a computer, implements a method for dynamically controllingpower usage in a power network, said method comprising the steps of:receiving data input that represents utility information; associatingsaid utility information with one of a plurality of system prioritylevels; associating said one of said plurality of system priority levelswith one of a plurality of switch state configurations each representinga particular configuration representing respective switch states of oneor more switchable power nodes in said power network, each said one ormore switchable power nodes having an associated priority level andcomprising a switch element that operates in a first state toelectrically couple a first subset of a plurality of power lines and asecond subset of said plurality of power lines and that operates in asecond state to electrically isolate said first subset of said pluralityof power lines from said second subset of said plurality of power lines,and a switch actuator that actuates said switch element to a switchstate, said switch state comprising one of said first state, said secondstate, and zero or more additional states; and generating computerinstructions to effect actuation of said respective switch actuators ofcorresponding one or more of said one or more switchable power nodesthat require actuation to comply with said respective switch stateconfiguration associated with said one of said priority levels that isassociated with said received utility information.
 26. The computerreadable storage medium of claim 25, wherein: the plurality of systempriority levels comprises at least three system priority levels each ofwhich is associated with different ones of the plurality of switch stateconfigurations.